Device having autorotation of solid body



Jan. 14, 1969 G. wim-Riss 3,422,234

DEVICE HAVING AUTOROTATION OF 'SOLID BODY med Maron 15. 1967 le @E la Q/ 74 fm y 56 /f l ATTORNEYS.

United States Patent O 11 Claims ABSTRACT F THE DISCLOSURE This specication 'discloses a construction for obtaining automatic rotation of a solid body. An actuator moves the solid body toward and from points of contact which are in a plane at an acute angle to the direction of the stroke of the solid body, and the contacts are olf center so that they cause a rocking of the solid body and a shifting of it into oblique positions. This shifting results in the generation of forces that have a tangential component which rotates the body through a small angle at the end of its stroke, thereby obtaining a wiping action at the contact points. The invention is 4disclosed as embodied in an electric switch, but it is not limited to such uses.

Brief description off the invention It is an object of this invention to provide a construction which causes a progressive rotary movement of a solid -body about an axis in response to movement of into oblique positions when it comes against the contacts, that lie in a plane which is at an acute angle to the axis. Because of this an-gular relation, the solid body shifts into oblique positons when it cornes against the contacts, and this movement causes the generation of a force having a tangential component that rotates the solid body with small increments of angular movement.

The result can be effected by having the points of contact in a plane normal to the axis of movement of the solid body toward and from the contacts if the contact surface of the solid body is set at an acute angle to the axis of movement. The important action is that when the body comes up against the contacts, it must rock into an oblique position. The angle of Obliquity can be very small.

The invention will be `described as applied to an electric switch in which the solid body is a movable contact of the switch, and at least some of the -other contacts are fixed switch contacts that cause the circuit of the switch to Iclose when the solid body touches the fixed contacts. The rotary action of the solid body gives it a wiping action on the fixed contacts and not only keeps the contacts clean but reduces wear to such an extent that the switch lasts indefinitely. The movable contact has a flat surface and the contact points are in a plane at an acute angle to the axis of movement, but the use of a sloping surface on the movable body and contact points in a plane normal to the axis of movement is to be considered a mere reversal of parts.

The invention can be used in devices other than switches and it is applica-ble to any constructions where it is desirable to have a solid body make small angles of rotary motion as an adjunct to its motion toward and from contacts at one end of its structure.

Other objects, features and advantages of the invention will appear or be pointed out as the description proceeds.

Brief description of the drawing In the drawing, forming a part hereof, in which like reference characters indicate corresponding parts in all the views;

3,422,234 Patented Jan. 14, 1969 ICC FIGURE 1 is a sectional view through an electric switch having an actuator constructed in accordance with this invention;

FIGURE 2 is a sectional view, on a somewhat reduced scale, taken on the line 2 2 of FIGURE 1; and

FIGURES 3 and 4 are diagrammatic sectional views, on the same scale as FIGURE 1, taken on the sectional lines 3 3 and 4-4 respectively, of FIGURE 2, but `showing the ball contacts.

Detailed description of the invention The electric switch shown in FIGURE 1 includes a housing 10 having an upper portion 12 which fits into a lower portion 14. There is a circumferential depression 16 in the upper portion 12 of the housing and extending under the upper end of the lower portoin 14.

The upper edge region of the lower portion 14 is bent inward to form a lip 18 which permanently secures together the upper and lower portions of the housing 10.

Within the lower end of the housing 10 there is a diaphragm 20 which seats against an annular shoulder 22 located under the peripheral portion of the diaphragm 20. Inward from the shoulder 22 there is a chamber 24 under the diaphragm 20; and this chamber 24 communicates with a fluid supply system through a passage 26.

The diaphragm 20 is made of natural or synthetic rubber, or any other elastomer which is flexible and which has enough stretch to distort to the extent required for the operation of this invention, as will be explained in connection with FIGURES 3 and 4. The circumferential portion of the diaphragm 20 is clamped down against the shoulder 22 kby a downwardly projecting cylindrcial extension 28 of a ball holder 30.

There is a hub element 32 secured to the center portion of the diaphragm 20. This sub element 32 can be connected to the diaphragm in the manner of a conventional diaphragm plate, but in the illustrated construction it has a portion extending through a central opening in the `diaphragm and an integral head 34 projecting radially outward to form a frusto-conical surface under the inner edge portion of the diaphragm. A contact plate 36 rests on top of the hub element 32, and there is preferably a washer 38 of slippery material such as nylon or polytetrafluorethylene between the contact plate 36 and the top surface of the hub element 32 to facilitate rotation of the contact plate 36.

The contact plate 36 is annular and its outside diameter is substantially equal to the diameter of the hubelement 32 and the washer 36; but there is a center opening 40 through the contact plate 36 which is of larger diameter than an upward extension 42, of the hub element 32, which projects through the opening 40.

The upward extension 42 is representative of restraining means for limiting transverse movement of the contact plate 36 on the washer 38. This transverse movement can also be restrained by having the outer circumferential portion of the hub element 32 extend upward around the circumference of the contact plate 36 so that the restraint is from the outside instead of the inside. However, in any case, it is a feature of the invention that the contact plate 36 has a limited transverse movement before being restrained, and that it can rotate by rolling on the cylindrical surface of the upward extension 42, or on the surface of any substitute restraining means.

In the preferred construction, a ring 44, held in place by a turned-over lip 46 at the top of the extension 42, prevents the contact plate 36 from coming off the upward extension 42 in an axial direction.

There are three contact balls 48, `50 land 52, located in openings in the ball holder 30. These contact balls 48, 50 and 52 fit into the ball holder 30 with press lits so that they are rigidly held in position by the ball holder.

3 Each of the balls 48, 50 and S2 is preferably at the same distance from the center line of the housing 10, but they are lat different axial distances from the neutral position of the diaphragm 20; that is, the centers of the balls 48, 50 and 52 deine a plane which is at an acute angle to .the longitudinal center line of the housing 10.

The ball holder 30 is clamped in position by the bottom edge of the upper portion 12 of the housing; but preferably with an electrical insulating washer 56 located between the top of the ball holder 30 and the upper portion 12 of the housing.

There are three substantially concentric helical springs of different diameter located in the housing above the ball contacts. These include a spring 58 which contacts with the ball 48, and a spring 60 which contacts with the ball 50. The electrical insulating washer 56 prevents contact of the spring 58 with the ball 50 and also prevents contact of the spring 60 with the ball 48. The third ball 52 can contact with either of the springs 58 or 60, or need not contact with them, depending upon the desired operation of the switch.

The third spring 62 contacts with a ange 64 on 'a pin 66 which has a rounded bottom surface 68 which iits into a complementary socket 70 to form, in effect, a balland-socket joint for exerting downward pressure on the hub element 32 of the diaphragm 20.

The upper end of the spring 62 is held down by a stepped washer 74 which can be moved up and down by an `adjusting screw 76 threaded through a hub 78 located :along the center line of the housing. This hub 78 lhas spokes 80 extending outward to a rim 82 which has a press lit in the upper portion 12 of the housing, and which bottoms against a shoulder 84.

A junction box 86 has terminal prongs 87 for connection with an outside circuit; and has conductors 88 and 90 extending downward into contact with the upper ends of the springs 58 and 60, respectively. Thus the junction box 86 is connected with the ball contacts 48 and 50; and when the contact plate 36 is touching the balls 48 and 5'0, as shown in FIGURE l, the circuit of the switch is closed.

When the diaphragm 20 is in its neutral position, that is, when it is subjected to equal fluid pressure against its upper and lower surfaces, the contact plate 36 is spaced from all of the contact balls 48, 50 and 52. When pressure in the chamber 24 increases, the diaphragm 20 ilexes up- -wardly and moves the contact plate 36 toward the balls 48, 50 and S2. Because of the fact that the balls are at different distances from the neutral position of the diaphragm 20, the plate 36 will strike the closest ball 48 before touching the others.

Further movement of the diaphragm 20 will then rock the contact plate 36 about itspoint of contact with the ball 48 until the contact plate strikes the next closest ball 50. This condition is shown in FIGURE 3, and with the balls `48 and 50 connected with the junction box for the electric circuit, this closes the circuit. Actually, the diaphragm 20 warps to some extent after contact of the plate 36 with the ball 48 prevents further upward movement of the diaphragm under the ball 48, but no attempt is made to show the warped diaphragm in FIGURE 3 because the rocking movement of the contact -plate 36- is more effectively shown by comparison with the position of the diaphragm 20 and hub element 32 at the time of rst contact of the plate 36 with the ball 48; and the diaphragm 20 and hub element 32 are shown in this position in dotted lines in FIGURE 3.

The position of the contact plate 36, as shown in FIG- URE 3, is rarely ever a stable condition, and the upward pressure under the diaphragm 20 continues to warp the diaphragm so that the hub element 32 and contact plate 36 rock about an axis connecting the points of contact of the plate 36 with the balls 48 and 50. This rocking movement brings the contact plate 36 up against the third ball 52. It will be evident that the closing of the switch can be made to occur when the contact plate 36 touches the third 4 ball 52. This result is obtained by merely making the closest ball 48 a dead contact.

FIGURE 4 shows the contact plate 36 in Contact with the ball 52 and the diaphragm 20 and hub element 32 are shown in the same dotted-line positions as in FIGURE 3.

The principle of the invention is illustrated in FIGURE 2 where the points of contacts of the plate 36 with the balls 48, 50 and 52 are indicated by the reference characters A, B and C, respectively. The stopping of the movement of the plate 36 by contact with the points A, B and C in sequence, produces a rotary movement of the plate 36 which is believed to be the result of the fact that the movements of the plate resulting from these contacts produce forces which are oi center and have, therefore, a tangential as well as a radial component. What is believed to be the effect of these forces will now be described.

When the plate 36 rocks about the point A, at least some component of its movement is toward the point B; and when it strikes the point B, motion along the line AB is stopped. Although the plate 36 can continue to move by rocking about the line AB as an axis, there is some inertia involved in the stopping of the movement of the plate 36 by contact with the point B. Apparently this inertia produces a force in the direction AB. This force, though it may be a very small component of the total inertia force, does have some tangential component which tends to rotate the plate 36 in a clockwise direction in FIGURE 2.

Further movement of the plate 36 is about the axis AB and this brings the plate into contact with the point C. If this axis of rotation were in a plane normal to the center line of the housing, and the plate 36 were centered on the extension 42 of the hub element, then the inertia force of the contact with the point C would appear to be through the center line of the housing and, therefore, radial. However, the contact plate 36 is in an oblique position because of the fact that all of the points A, B and C are at different distances from the neutral plane of the diaphragm 20, and the contact plate 36 is substantially never centered. Therefore, the inertia force which results from the contact of the plate 36 with point C, is also 01T center and has a tangential as well as a radial component.

The contact plate 36 tends to slide transversely when it strikes the point B and when it strikes the point C, and it also rolls with a planetary or epicyclic movement about the surface of the upward extension 42 of the hub element. FIGURE 2 shows the contact plate 36 in contact with the extension 42.

The actual forces involved depend upon the location of the center of gravity of the contact plate 36 and upon its point or axis of gyration, or its direction of movement when about the single point A. The analysis of the force involved is enormously complicated, even impossible to compute, because the directions change with warping of the diaphragm and the direction of movement about the point A may be in different directions at different times, depending upon differences in elasticity and local temperature variations in the diaphragm, and also upon which phase of its rotation around the extension 42 the plate 36 may occupy at any particular moment of its rocking movement.

However, actual results have proven that the construction does produce a rotary movement of the plate 36 which distributes wear and increases indefinitely the life ofthe switch as compared with other switches having similar ball contacts but not having any rotary movement of the contact plate 36.

The preferred embodiment of the invention has been illustrated and described, but changes and modifications can be made and some features can be used in different combination without departing from the invention as defined in the claims.

What is claimed is:

1. Apparatus for obtaining automatic rotation of a solid body that moves toward and from contacts at one end of its stroke, including in combination a solid body, an actuator that moves the solid body along a generally longitudinal axis, contacts toward and from which the solid body moves and which the solid body touches at one end of its stroke, said contacts being offset from a line along which the center of gravity of the solid body moves, and said contacts being in a plane, the points on the solid body that touch the contacts also being in a plane, one of said planes being at an acute angle to the generally longitudinal axis whereby the solid body is shifted into an oblique position when it comes up against said contacts, said shifting motion producing a force having a tangential component that rotates the solid body.

2. The apparatus described in claim 1 characterized by the contacts being three spherical surfaces at angularly spaced locations around the generally longitudinal axis alorig which the solid body moves.

3. The apparatus described in claim 2 characterized by the three spherical surfaces having their points of contac't with the solid body in a plane which is at an acute angle -to the generally longitudinal axis, and the face of thersolid body that touches the contacts having a plane surface that is substantially normal to said generally longitudinal axis prior to shifting of the solid body into an oblique position.

4. The apparatus described in claim 2 characterized by the contacts being part of the surface of balls, a holder in which the balls are fixed, the balls being of the same diameter as on another and having their centers in a plane which is at an acute angle to the generally longitudinal axis.

5. The apparatus described in claim 4 characterized by the apparatus being an electric switch with two of the balls electrically connected with opposite sides of a circuit which is to be controlled, and the solid body being an electrical conductor and constituting a movable contact of the switch for closing the circuit when it touches the balls and connected `with opposite sides of the electrical circuit, the rotary movement of the movable contact serving to `wipe the other contacts to keep them clean and to distribute wear over the surface of the movable contact.

6. The apparatus described in claim 5 characterized by a hermetically sealed housing, the solid body and the balls being inclosed with said housing, a exible diaphragm forming a partition across the housing and forming one end of a chamber that contains the solid body and the balls, the solid .body being carried by the diaphragm and the diaphragm constituting the actuator for moving the solid body in one direction, and a second chamber on the side of the diaphragm opposite the hermetically sealed chamber for receiving working fluid to Hex the diaphragm and to move the solid body.

7. The apparatus described in claim 1 characterized by the actuator being a flexible diaphragm with which the solid body is connected, said diaphragm being distortable to effect the shifting of the solid body into an oblique position `when it comes against the contacts.

8. The apparatus `described in claim 1 characterized by the actuator being a flexible diaphragm closing one end of a chamber in which the pressure is changed to operate the actuator, a diaphragm plate covering the midportion of the diaphragm, an upward extension of the center portions of the diaphragm plate, the solid body being a generally annular ring that rests on the part of the diaphragm plate which extends radially upward from the upward extension and being rotatable on said part a-s a bearing.

9. The apparatus described in claim 8 characterized by the diaphragm being distortable to let the diaphragm plate, shift into position at an acute angle to the generally longitudinal axis along which the solid body moves toward and from the contacts, a coating of low friction material on the part of the diaphragm plate on which the solid body rests, the inside diameter of the solid body being larger than the maximum width of the upward extension so that the solid body is free to shift transversely on the diaphragm plate in addition to its rotary movement around the upward extension.

10. The apparatus described in claim 9 characterized by the upward extension of the diaphragm plate being substantially cylindrical whereby the surface around the inner edge of the solid body rolls on the cylindrical surface of the upward extension with an orbital movement as it rotates, and restraining means on the upward extension for preventing the solid body from moving upward beyond a given limit.

11. The apparatus described in claim 8 characterized by resilient means urging the solid body in the diaphragm away from the contacts, said resilient means including a pin tting into a socket in a center region of the diaphragm plate with the confronting sur-faces of the pin and socket shaped to provide a universal bearing on which the diaphragm plate can move into oblique positions with respect to said generally longitudinal axis.

FOREIGN PATENTS 221,640 11/ 1961 Austria. 6,903 r8/ 1949 France. 1,147,651 4/ 1963 W. Germany.

ROBERT K. SCHAEFER, lPrimary Examiner. H. BURKS, Assistant Examiner.

U.S. C1. X.R. 20G-166 

